D17100 changed things so that bin/repository gets an explicit TERM=dumb. As a side effect, this threw away the rest of the environment for installs with no "E" in variables_order. In particular, this means that "PHABRICATOR_ENV" may be dropped.
Since we're churning a lot and it's already Thursday, just patch this for now by reading "PHABRICATOR_ENV" out of the environment. I'll pursue more ambitious changes to fix this correctly after master promotes.